Photosensitizer composite and uses thereof

ABSTRACT

A composite nanomaterial of ZnO impregnated by, e.g., a green copper phthalocyanine compound (CuPc) can be an efficient solar light photocatalyst for water remediation. The composite may include hollow shell microspheres and hollow nanospheres of CuPc-ZnO. CuPc may function as a templating and/or structure modifying agent, e.g., for forming hollow microspheres and/or nanospheres of ZnO particles. The composite can photocatalyze the degradation of organic pollutants such as crystal violet (CV) and 2,4-dichlorophenoxyacetic acid as well as microbes in water under solar light irradiation. The ZnO—CuPc composite can be stable and recyclable under solar irradiation.

STATEMENT OF PRIOR DISCLOSURE

Aspects of the present disclosure are described in Hanan H. Mohamed,Ines Hammami, Sultan Akhtar, Tamer E. Youssef, “Highly efficientCu-phthalocyanine-sensitized ZnO hollow spheres for photocatalytic andantimicrobial applications,” Composites Part B: Engineering, Volume 176,2019, 107314, https://doi.org/10.1016/j.compositesb.2019.107314, whichpublished online on August 13209 and is incorporated herein byreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to metallophthalocyanine composites withmetal oxides, particularly including copper-phthalocyanine and/or zincoxide, methods of making such composites, and to the use of suchcomposites in decomposing organic compounds, particularly organic dyes,in water and/or modifying ZnO morphology with one or moremetallophthalocyanines.

Description of the Related Art

With growing populations, water pollution has correspondingly become aworldwide issue, with roughly 14,000 people dying each day due to waterpollution. Water pollution not only affects the environment and humanwell-being, but also disrupts the balance of the ecosystem. Many factorscan cause water pollution such as herbicides, pesticides, toxic metalions, and pathogens. Therefore, treating wastewater before its releaseback into the environment is crucial.

Organic dyes are an important synthetic component of hazardous waterpollutants. Several methods have been used in the art to treatwastewater containing organic dyes, including electrochemical oxidationtechniques using metal plates, adsorption methods, and photocatalyticmethods. Photocatalysis using semiconductor nanomaterials has gainedattention as a cost effective, green, and efficient method fordecomposing various organic and inorganic pollutants.

When a semiconductor nanomaterials is irradiated UV or visible lightwith at least the same energy as the band gap energy, electron-holepairs (e⁻/h⁺) are generated in the conduction band and the valence bandof the semiconductor, respectively. The photo-generated charge carriers,i.e., electrons and holes, then migrate to the surface of thesemiconductor nanoparticle and potentially become efficient reducing oroxidizing species.

Different semiconductor nanomaterials have been used for photocatalyticoxidation and reduction processes, including TiO₂, ZnO, CdO, CdS, ZnS,etc. Among the various known semiconductor nanomaterials, zinc oxide(ZnO), particularly as a nanomaterial, has become a widely investigatedmetal oxide semiconductor as a suitable material for widespreadenvironmental and energy applications due to its distinctivecharacteristics including environmental tolerability, photocatalyticactivity, low cost, and biocompatibility. However, ZnO has thedisadvantage that it is susceptible to two dissolution processes duringthe heterogeneous photocatalysis. The first dissolution process ischemical dissolution with species in solution and the second dissolutionprocess is the photochemical dissolution, where the photogenerated holescan oxidize the ZnO. In addition, the photocatalytic activity of ZnO islimited by a high rate of charge carrier recombination and limitedvisible light absorption.

Several approaches have been attempted at decreasing the dissolutionrate of ZnO nanoparticles, including surface and morphologymodifications. Other approaches have focused on extending the absorptionrange of ZnO nanomaterials, for example, by metal/non-metal doping,metal loading, coupling with other semiconductor, hybridization withcarbon nanomaterials such as graphene oxide (GO), and dye sensitization.Amongst these methods, photosensitizing ZnO nanomaterials withorganometallic dyes has shown potential as an efficient and convenientmethod.

Recently, ZnO sensitized with cobalt-phthalocyanine indicated efficientvisible light photocatalysis for cyanide degradation. ZnO nanorodsensitized with nickel phthalocyanine also exhibited photocatalyticactivity for Rhodamine B transformation. Photocatalytic degradation ofRhodamine 6G has also been achieved using zinc phthalocyanine in thepresence of ZnO. Other efforts in the art are known.

CN 103134753 A by Li et al. (M. Li) discloses a zinc oxide compositematerial modified by copper phthalocyanine, its synthesis and use. M.Li's materials are zinc oxide microporous blocks with surfaces modifiedby copper phthalocyanines, having specific surface areas of 8 to 9 m²/g,a microporous block length of 5 to 10 μm, a microporous block height of10 to 20 μm, and a pore diameter in each microporous block of 20 to 70nm. M. Li does not disclose a copper phthalocyanine-zinc oxide compositecomprising optionally hollow micro-spheres having average diameters offrom 0.5 to 5.0 m and optionally hollow nano-spheres having averagediameters of from 50 to 450 nm.

U.S. Pat. No. 9,700,882 to Ahmed et al. (Ahmed) discloses zinc-basednanohybrids having zinc oxide nanostructures connected to zincphthalocyanine molecules via biologically important ligands. Ahmed'snanohybrid has photocatalytic properties and photodegrades waterpollutants, such as methyl orange. Ahmed's material may be ananoparticle, with an average diameter of 50 to 100 nm, and/or anontubular nanorod, with an average largest diameter of 50 to 100 nm anda length of 0.3 to 5 μm. Ahmed requires a bridging compound such as aterminal dicarboxylic acid or amino acid, but does not disclose usingcopper.

CN 107955398 A by Li et al. (Q. Li) discloses a composite pigment withthe surface coated with phthalocyanine blue. Q. Li's method useselectrostatic interaction of copper phthalocyanine (CuPc) with oppositecharges and a laminar oxyhydrate nano-material with a similarhydrotalcite structure to directly co-assemble to obtain a laminar nanocomposite material. Q. Li's structure has CuPc molecules and a laminaroxyhydrate layer are in monomolecular layer vertical arrangement, withan increased interlayer spacing of laminar oxyhydrate. While Q. Li usesZnCl₂—alongside AlCl₃ and MgCl₂— in its process with CuPc, Q. Li'sprocess is sonicated for up to 2 hours, then treated at a pH of at least10 for at least 8 hours, to obtain a surface coated blue phthalocyaninecomposite. Q. Li does describe the morphology of its product.

Mater. Sci. Semicond. Proc. 2017, 77, 74-82 by Maya-Trevino et al.(Maya) discloses ZnO modified with 0.1 and 0.5 wt. % copper (11)phthalocyanine (CuPc) synthesized via a sol-gel method. Maya's ZnO—CuPcmaterial can degrade methylene blue and KCN under 290 to 390 nm and 400to 700 nm light sources. Maya does not use a hydrothermal synthesis, andproduces nanosized particles of customary bar morphology that tend toagglomerate.

J. Phys. Chem. C 2014, 118(1), 691-699 by Ghosh et al. (Ghosh) disclosesnanocomposites of copper phthalocyanine (CuPc) and ZnO nanoparticlesgrown in situ in a colloidal solution of CuPc using zinc acetate asprecursor and NaOh as precipitating agent. Ghosh forms a network ofn-type ZnO with p-type CuPc, with ZnO nanorods firmly attached to theCuPc in the composite. Ghosh does not describe nano- or micro-spheres,hollow or otherwise, nor biocidal activity.

Solar Energy Mater. Solar Cells 2006, 90(7-8), 933-943 by Sharma et al.(Sharma) discloses a blend of p-type copper phthalocyanine (CuPc) andn-type zinc oxide (ZnO) nanoparticle, describing an efficient electrontransfer between donor (CuPc) and acceptor (ZnO) nanoparticle in acomposite thin film structure. Sharma also describes that thecapacitance-voltage characteristics of the ZnO—CuPc device support theformation of a bulk heterojunction between CuPc and ZnO nanoparticles,but does not disclose spheroid morphologies, nor antiseptic activity.

Appl. Surf Sci. 2011, 257(15), 6908-6911 by Luo et al. (Luo) discloseshybrid film of zinc oxide (ZnO) and tetrasulfonated copperphthalocyanine (TSPcCu) grown on an indium tin oxide (ITO) glass by aone-step cathodic electrodeposition from aqueous mixtures of Zn(NO₃)₂,TSPcCu, and KCl. Luo reports that adding TSPcCu influences themorphology and crystallographic orientation of ZnO, and describes ananosheet stack of ZnO with a porous surface structure advantageous foradsorbing organic dyes. Luo does not disclose a spheroid morphology forits materials, much less a hollow nano-sphere morphology, especially fora copper phthalocyanine-zinc oxide composite.

In light of the above, a need remains for composite materials comprisingphthalocyanine, copper, and zinc oxide, particularly having spheroidmorphology and more particularly with hollow spherical shapes,particularly for decomposing organic contamination in water, such asorganic dyes, pharmaceuticals, and the like, and methods of making andusing such composites.

SUMMARY OF THE INVENTION

Aspects of the invention provide composite materials, comprising: acopper phthalocyanine compound; and ZnO, wherein the composite materialcomprises first spheroid particles having an average diameter in a rangeof from 50 to 450 nm and second spheroid particles of an average outerdiameter in a range of from 0.5 to 5 μm. Such materials may be modifiedby any permutation of the features described herein, particularly thefollowing.

The copper phthalocyanine compound may have a structure of a formula

wherein Ar is an aryl group, Y is independently O or S, Z isindependently a sulfonate, phosphonate, or carboxylate, m isindependently 0 or 1, and n is independently 0, 1, or 2. The aryl groupmay be phenyl, naphthyl, biphenyl, pyridyl, pyrrole, thiophene,pyrazole, imidazole, 1,2,4-triazole, 1,2,3-triazole, oxazole, isoxazole,isothiazole, thiazole, pyrimidine, pyridazine, pyrazine, 1,2,4-triazine,1,3,5-triazine, indole, isoindole, indolizine, indazole, benzimidazole,7-azaindole, 4-azaindole, 5-azaindole, 6-azaindole, 7-azaindazole,pyrazolo[1,5-a]pyrimidine, purine, benzofuran, isobenzofuran,benzo[c]thiophene, benzo[b]thiophene, benzo[d]isoxazole,benzo[c]isoxazole, benzo[d]isothiazole, benzo[c]isothiazole,benzo[d]oxazole, benzo[d]thiazole, benzo[c][1,2,5]thiadiazole, adenine,quinoline, isoquinoline, 4-quinolizine, quinoxaline, phthalazine,quinazoline, cinnoline, 1,8-napththyridine, pyrido[3,2-d]pyrimidine,pyrido[4,3-d]pyrimidine, pyrido[3,4-b]pyrazine, pyrido[2,3-b]pyrazine,pteridine, acridine, or phenazine. The copper phthalocyanine compoundmay be one in which Ar is phenyl, Y is S, Z is sulfonate, m is 1, and/orn is independently 0 or 1.

The copper phthalocyanine compound may be present in an amount of from2.5 to 15 wt. %, relative to a total material weight.

Inventive materials may be synthesized hydrothermally.

Inventive materials may have a molar ratio of Cu to Zn in a range offrom 3:1 to 1:3.

The first spheroids may have a sphericity of at least 0.85. The secondspheroids may comprise hollow spheres have a sphericity of at least 0.9and/or hollow hemispheres, which when extrapolated to spheres, may havea sphericity of at least 0.9. The second spheroids, particularlyincluding hollow hemispheres and/or spheres, may have nanorods,protruding ourtwardly, orthogonally to spherical surfaces, and thenanorods may have an average diameter in a range of from 1 to 250 nm.

Aspects of the invention provide methods of synthesizing a compositeincluding hollow micro(hemi)spheres and/or nanospheres, which methodsmay comprise: combining a zinc compound and a copper phthalocyaninecompound in a solvent to form a reaction mixture; and heating thereaction mixture at a temperature in a range of 100 to 200° C. for atreatment time in a range of 10 to 30 hours, wherein a molar ratio ofthe zinc compound to the copper phthalocyanine compound is in a range3:1 to 1:3.

The copper phthalocyanine compound may comprise at least 75 wt. % ofsulfonated tetra thiophenyl copper phthalocyanine.

The solvent may comprise at least 75 wt. %, relative to total solventweight, of a mixture of ethanol and diethylene glycol.

The zinc compound may comprise at least 75 wt. %, relative to total zincsalt weight, of zinc acetonylacetonate.

The heating may be conducted at a pressure in a range of from greaterthan 1 to 50 atm.

The hollow micro(hemi)spheres may have a diameter in a range of from 0.5to 5.0 μm, and/or wherein the hollow nanospheres may have a diameter ina range of from 50 to 450 nm.

Aspects of the invention provide methods of decomposing one or moreorganic compounds in water, which methods may comprise: contacting anypermutation of the inventive composite material(s) as described hereinwith an aqueous medium comprising the organic compound to form amixture; and irradiating the mixture with ultraviolet and/or visiblelight. The mixture may further comprise 0.05 to 0.4 wt. % hydrogenperoxide. The organic compound may comprise an organic dye.

Aspects of the invention provide methods for treating water, which maycomprise: irradiating a mixture comprising an aqueous fluid comprising afirst amount of bacteria with any permutation of the inventive compositematerial(s) as described herein, with ultraviolet and/or visible lightto obtain a treated aqueous fluid comprising a second amount ofbacteria, wherein the first amount is greater than the second amount ofbacteria.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 shows a synthetic scheme for the sulfonated phenyl sulfide ofcopper(II)phthalocyanine, (PhS.SO₃Na)₄CuPc (where CuPc is the sulfonatedphenyl sulfide of copper(II) phthalocyanine);

FIG. 2 shows x-ray diffraction (XRD) patterns of pure ZnO (lowerpattern) and an exemplary CuPc-ZnO nanocomposite (upper pattern);

FIG. 3 shows Raman spectra of pure ZnO (lower spectrum), pure CuPc(middle spectrum), and an exemplary CuPc-ZnO nanocomposite (upperspectrum);

FIG. 4 shows Fourier-transform Infrared (FT-IR) spectra of pure ZnO(lower spectrum), pure CuPc (middle spectrum), and an exemplary CuPc-ZnOnanocomposite (upper spectrum);

FIG. 5A shows diffuse reflectance UV-vis spectra of pure ZnO (upperspectrum), pure CuPc (lower spectrum), and an exemplary CuPc-ZnOnanocomposite (middle spectrum);

FIG. 5B shows Kubelka-Munk plots for the band gab energies of the pureZnO (lower spectrum) and an exemplary CuPc-ZnO nanocomposite (upperspectrum) showing the intercept of the tangents of Kubelka-Munk plots;

FIG. 6A shows a scanning electron microscope (SEM) image of pure ZnO;

FIG. 6B shows an SEM image of an exemplary CuPc-ZnO nanocomposite withselected opening ends of the hollow spheres highlighted by arrowheads;

FIG. 7A shows a transmission electron microsope (TEM) images of pure ZnOon 500 nm scale;

FIG. 7B shows a TEM image of pure ZnO on 100 nm scale;

FIG. 7C shows a selected area electron diffraction (SAED) pattern ofpure ZnO;

FIG. 7D shows a TEM image of an exemplary CuPc-ZnO nanocomposite on 500nm scale;

FIG. 7E shows a TEM image of an exemplary CuPc-ZnO nanocomposite on 200nm scale;

FIG. 7F shows a TEM image of an exemplary CuPc-ZnO nanocomposite on 100nm scale;

FIG. 8 shows thermogravimetric analysis (TGA) curves of pure ZnO (upperspectrum), pure CuPc (lower spectrum), and an exemplary CuPc-ZnOnanocomposite (middle spectrum);

FIG. 9A shows UV-vis absorption spectra of an aqueous solution ofCrystal Violet (CV) during visible light irradiation in the presence ofan exemplary CuPc-ZnO nanocomposite with H₂O₂ at pH 5;

FIG. 9B shows concentration-based (C/C₀) photocatalytic degradationefficiency for Crystal Violet (CV) over irradiation time at pH 5 withdifferent materials, CuPc (top plot), ZnO (2^(nd) plot from top), anexemplary CuPc-ZnO nanocomposite (2^(nd) plot from bottom), and anexemplary CuPc-ZnO nanocomposite with H₂O₂ (bottom plot);

FIG. 9C shows pH-based photocatalytic degradation efficiency for CrystalViolet (CV) over irradiation time with an exemplary CuPc-ZnOnanocomposite with H₂O₂ (i.e., CuPc-ZnO—H₂O₂) at different pH values, pHof 2.5 (top plot), pH of 10 (2^(nd) plot from top), pH of 7.5 (2^(nd)plot from bottom), and pH of 5 (bottom plot);

FIG. 9D shows charts indicating the recyclability of pure ZnO and anexemplary CuPc-ZnO nanocomposite for the photocatalytic degradationefficiency for Crystal Violet (CV) over irradiation time at pH 5;

FIG. 10A shows UV-vis absorption spectra of an aqueous solution of2,4-dichlorophenoxyacetic acid (2,4-D) during solar light irradiation inthe presence of an exemplary CuPc-ZnO nanocomposite with H₂O₂ at pH 5;

FIG. 10B shows plots based on the UV-vis absorption spectra showingvariation of percent concentration based on initial concentration(C/C₀)and percent total organic content based on initial total organic content(TOC/TOC₀) with irradiation time of an aqueous solution of2,4-dichlorophenoxyacetic acid (2,4-D) during solar light irradiation inthe presence of an exemplary CuPc-ZnO nanocomposite with H₂O₂ at pH 5;

FIG. 11 shows a photograph of semi-solid agar plates exhibiting theeffect of an exemplary CuPc-ZnO nanocomposite against E. coli; and

FIG. 12 shows a proposed pictorial mechanism of the sensitizedphotocatalysis using an exemplary CuPc-ZnO nanocomposite.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Aspects of the invention provide composite materials, comprising: acopper phthalocyanine compound, which may be substituted as detailedherein, as well as with methyl, ethyl, fluoro, chloro, hydroxyl,sulfonate, carboxylate, and/or nitro groups in place of 1, 2, 3, 4, 5,6, 7, or 8 hydrogens, particularly upon aryl groups; and ZnO. Thecomposite material may comprise first spheroid particles having anaverage diameter in a range of from 50 to 450 nm, e.g., at least 50,62.5, 75, 87.5, 100, 112.5, 125, 137.5, 150, 162.5, 175, 187.5, 200,212.5, 225 237.5, or 250 nm and/or 450, 437.5, 425, 417.5, 400, 387.5,375, 362.5, 350, 337.5, 325, 312.5, 300, 287.5, 275, 262.5, or 250 nm,and second spheroid having an average outer diameter in a range of from0.5 to 5 μm, e.g., at least 0.5, 0.75, 0.875, 1, 1.125, 1.25, 1.375,1.5, 1.625, 1.75, 1.875, 2, 2.125, or 2.5 μm and/or up to 5, 4.75, 4.5,4.25, 4, 3.75, 3.5, 3.375, 3.25, 3.125, 3, 2.875, 2.75, 2.625, 2.5,2.375, 2.25, 2.125, 2, 1.875, or 1.75 μm. The second spheroids maycomprise at least 50, 60, 70, 75, 80, 85, 90, or 95% hemispheroid,and/or may have a morphology akin to a durian or rambutan (or hybridthereof). The hemispheroids may have a morphology akin to a papakha hat,with orthogonally-oriented fuzz-like protrusions, view by SEM on 200 nmscale, from tangents to the spheroid surface.

The copper phthalocyanine compound may have a structure of a formula

wherein Ar is an aryl group, such as phenyl, naphthyl, biphenyl,pyridyl, pyrrole, thiophene, pyrazole, imidazole, 1,2,4-triazole,1,2,3-triazole, oxazole, isoxazole, isothiazole, thiazole, pyrimidine,pyridazine, pyrazine, 1,2,4-triazine, 1,3,5-triazine, indole, isoindole,indolizine, indazole, benzimidazole, 7-azaindole, 4-azaindole,5-azaindole, 6-azaindole, 7-azaindazole, pyrazolo[1,5-a]pyrimidine,purine, benzofuran, isobenzofuran, benzo[c]thiophene, benzo[b]thiophene,benzo[d]isoxazole, benzo[c]isoxazole, benzo[d]isothiazole,benzo[c]isothiazole, benzo[d]oxazole, benzo[d]thiazole,benzo[c][1,2,5]thiadiazole, adenine, quinoline, isoquinoline,4-quinolizine, quinoxaline, phthalazine, quinazoline, cinnoline,1,8-napththyridine, pyrido[3,2-d]pyrimidine, pyrido[4,3-d]pyrimidine,pyrido[3,4-b]pyrazine, pyrido[2,3-b]pyrazine, pteridine, acridine, orphenazine, preferably phenyl, biphenyl and/or naphthyl, Y isindependently O or S, Z is independently a sulfonate, phosphonate, orcarboxylate, m is independently 0 or 1, and n is independently 0, 1, or2. The copper phthalocyanine compound may be one in which Ar is phenyl,Y is S, Z is sulfonate, m is 1, and/or n is independently 0 or 1.

The copper phthalocyanine compound may be present in an amount of from2.5 to 15 wt. %, relative to a total composite material weight, e.g., atleast 2.5, 3, 3.5, 4, 4.5, 4.75, 5, 5.25, 5.5, 5.75, 6, 6.25, 6.5, 6.75,7, 7.25, 7.5, 7.75, 8, 8.25, 8.5, 8.75, 9, 9.25, or 9.5 wt. % and/or upto 15, 14.5, 14, 13.5, 13, 12.5, 12, 11.75, 11.5, 11.25, 11, 10.75,10.5, 10.25, 10, 9.75, 9.5, 9.25, 9, 8.75, 8.5, 8.25, or 8 wt. %.

Inventive materials may be synthesized hydrothermally, i.e., by heatinga solution containing the starting materials in a closed vessel,generally above standard pressure, e.g., above 1, 1.05, 1.1, 1.25, 1.5,2, 2.5, 3, 4, 5, 7.5, 10, or 15 atm and/or up to 100, 75, 65, 60, 55,50, 45, 40, 35, 30, 25, 20, 17.5, 15, 12.5, 10, 7.5, or 5 atm,preferably in a single step.

Inventive materials may have a molar ratio of Cu to Zn in a range offrom 3:1 to 1:3, e.g., at least 3:1, 2.75:1, 2.5, 2.25, 2:1, 1.875:1,1.85:1, 1.8:1, 1.75:1, 1.7:1, 1.65:1, 1.6:1, 1.55:1, 1.5:1, 1.45:1,1.4:1, 1.35:1, 1.3:1, 1.25:1, 1.2:1, 1.15:1, 1.1:1, 1.05:1, 1:1 and/orup to 1:3, 1:2.75, 1:2.5, 1:2.25; 1:2, 1:1.9, 1:1.85, 1:1.8, 1:1.75,1:1.7, 1:1.65, 1:1.6, 1:1.55, 1:1.5, 1:1.45, 1:1.4, 1:1.35, 1:1.3,1:1.25, 1:1.2, 1:1.15, 1:1.1, 1:1.05 or 1:1, or this molar relationshipmay be present in a hydrothermal solution used for the synthesis ofinventive nanocomposites.

The first spheroids may have a sphericity of at least 0.85, 0.875, 0.9,0.905, 0.91, 0.915, 0.92, 0.925, 0.93, 0.935, 0.94, 0.945, 0.95, 0.955,0.96, 0.965, 0.97, 0.975, 0.98, 0.985, 0.99, or 0.995. The firstspheroids may be hollow and/or may comprise at least 75, 80, 85, 90, 91,92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9%spherical particles. The second spheroid particles may comprise hollowhemispheres and/or hollow spheres. The hollow hemispheres, whenextrapolated to spheres, and/or the hollow spheres may have a sphericityof at least 0.9, 0.905, 0.91, 0.9125, 0.915, 0.9175, 0.92, 0.9225,0.925, 0.9275, 0.93, 0.9325, 0.935, 0.9375, 0.94, 0.9425, 0.945, 0.9475,0.95, 0.9525, 0.955, 0.9575, 0.96, 0.9625, 0.965, 0.9675, 0.97, 0.9725,0.975, 0.9775, 0.98, 0.9825, 0.985, 0.9875, 0.99, 0.9925, 0.995, or0.9975. The (hollow) hemispheres may constitute, e.g., at least 75, 85,90, 92.5, 95, or 97.5%, of the second spheroid particles. The optionallyhollow hemispheres and/or spheres may have nanorods, protrudingourtwardly, orthogonally to spherical surfaces, and the nanorods mayhave an average diameter in a range of from 1 to 250 nm, e.g., 1, 2.5,5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5, or 30 nm and/or up to250, 225, 200, 187.5, 175, 162.5, 150, 137.5, 125, 112.5, 100, 87.5, 75,62.5, 50, 37.5, or 25 nm.

Aspects of the invention provide methods of synthesizing compositesincluding preferably hollow micro(hemi)spheres and/or preferably hollownanospheres. Inventive synthetic methods may comprise: combining a zinccompound and a copper phthalocyanine compound in a solvent to form areaction mixture; and heating the reaction mixture at a temperature in arange of 100 to 200° C., e.g., at least 100, 105, 110, 115, 120, 125,130, 135, 140, 145, or 150° C. and/or up to 200, 195, 190, 185, 180,175, 170, 165, 160, 155, 150° C., for a treatment time in a range of 10to 30 hours, e.g., at least 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14,14.5, 15, 15.5, 16, 16.5, 17, 17.5, or 18 hours and/or up to 30, 29, 28,27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, or 12 hours,wherein a molar ratio of the zinc compound to the copper phthalocyaninecompound is in a range 3:1 to 1:3 (or any ratio described above). Usefulzinc compounds may be chelates and/or salts of zinc, particularly zinc(11), comprising, e.g., acetylacetonate (acac, or 2,4-pentandione),3,5-heptanedione, 3-methyl-2,4-pentanedione, 2-oxobutyric acid, methyl3-oxopentanoate, ethyl propionylacetate, ethyl pivaloylacetate, methylpivaloylacetate, ethyl 3-oxohexanoate, methyl 3-oxohexanoate, methyl3-oxo-3-phenylpropanoate, ethyl 3-oxo-3-phenylpropanoate, ethylisobutyrylacetate, methyl isobutyrylacetate, 1,2-diaminoethane,ethylenediaminetetraacetate, ethylene glycol-bis(O-aminoethylether)-N,N,N′,N′-tetraacetic acid, diethylenetriamine penta is aphosphonic acid, aminotris(methylenephosphonic acid), ethylenediaminetetra(methylene phosphonic acid), diethylenetriamine, ammonia, hydrate,hydroxyde, nitrate, nitrite, chloride, bromide, iodide, phosphate,sulfate, carbonate, acetate, oxylate, formate, citrate, phenoxide,salicylate, and/or lactate, as well as, e.g., C1, C2, C3, C4, C5, C6,C7, C8, C9, C10, C11, C12, C13, C14, and/or C16 alkyl sulfonate(s),phosphonate(s), and/or carboxylates.

The copper phthalocyanine compound may comprise at least 75, 80, 85, 90,91, 92, 92.5, 93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt.% of sulfonated tetra thiophenyl copper phthalocyanine, in any formdescribed herein.

The solvent may comprise at least 75, 80, 85, 90, 91, 92, 92.5, 93, 94,95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. % relative to totalsolvent weight, of a mixture of an alcohol and a glycol, such asethylene glycol, methanol, ethanol, isopropanol, propanol, n-butanol,diethylene glycol, triethylene glycol, and/or tetraethylene glycol,especially, ethanol and diethylene glycol.

The zinc compound may comprise at least 75, 80, 85, 90, 91, 92, 92.5,93, 94, 95, 96, 97, 97.5, 98, 99, 99.1, 99.5, or 99.9 wt. %, relative tototal zinc salt weight, of zinc acetonylacetonate.

The heating and/or the hydrothermal synthesis may be conducted at apressure in a range of from greater than 1 to 50 atm (or any of theabove values or ranges).

The second spheroids, e.g., hollow micro(hemi)spheres, may have adiameter in a range of from 0.5 to 5.0 μm (or any of the above values orranges), and/or wherein the first spheroid particles, e.g., hollownanospheres, may have a diameter in a range of from 50 to 450 nm (or anyof the above values or ranges).

Aspects of the invention provide methods of decomposing one or moreorganic compounds in water, which methods may comprise: contacting anypermutation of the inventive composite material(s) as described hereinwith an aqueous medium comprising the organic compound to form amixture; and irradiating the mixture with ultraviolet and/or visiblelight. The mixture may further comprise 0.05 to 0.4 wt. % hydrogenperoxide, relative to the starting material weight (excluding solvent),e.g., at least 0.1, 0.125, 0.15, 0.175, 0.2, 0.225, 0.25, 0.275, 0.3, or0.33 wt. % and/or up to 0.4, 0.375, 0.35, 0.325, 0.3125, 0.3, 0.2875,0.275, 0.2625, 0.25, 0.245, 0.2375, 0.235, 0.2275, 0.22, 0.21, 0.205, or0.2 wt %. The organic compound may comprise an organic dye, such as,e.g., anionic, cationic, azo, diazo, etc., dyes. The contaminant maycomprise dyes, soaps, oils, and adhesives, e.g., fluorescent and/orphosphorescent compounds, chromophores and/or colorless compounds. Theorganic contaminant may comprise a dye, including acid dyes, basic dyes,direct dyes, reactive dyes, mordant dyes, etc., such as one or moreazodyes, acridine dyes, anthraquinone dyes, arylmethane dyes, diarylmethanedyes, triarylmethane dyes, phthalocyanine dyes, quinone-imine dyes, azindyes, eurhodine dyes, safranine dyes, indamines, indophenol dyes,oxazine dyes, oxazone dyes, thiazine dyes, thiazole dyes, xanthene dyes,fluorene dyes, pyronine dyes, fluorone dyes, rhodamine dyes, or mixturesof these. The organic compound may comprise methylene blue and/ormalachite green. The organic compound may comprise a pharmaceutical,such as beta-blockers, antipyretics, analgesics, antimalarials,antibiotics, antiseptics, anticoagulants, antidepressants, anticancerdrugs, antiepileptics, antipsychotics, antivirals, sedatives,antidiabetic, hormone replacements, oral contraceptives, stimulants,tranquilizers, statins, or mixtures of two or more of any of these.Beyond beta blockers, relevant compound classes may include5-alpha-reductase inhibitors, angiotensin 11 receptor antagonists, ACEinhibitors, alpha-adrenergic agonists, dopamine agonist, dopamineantagonist, incretin mimetics, nonsteroidal anti-inflammatorydrugs—cyclooxygenase inhibitors, proton-pump inhibitors, renininhibitors, selective glucocorticoid receptor modulators, selectiveserotonin reuptake inhibitors, or mixtures of two or more of any ofthese. Biopharmaceuticals, such as antibodies, proteins, nucleotidesequences/splices, etc., may also be degraded. The contaminant compoundmay comprise one or more pharmaceuticals and/or chemical, paper, dye,wood, adhesive, etc., manufacturing byproducts not exclusivelyconsisting of inorganic compounds, and the organic material issubstantially or completely soluble in the water. The sufficiency of themethod may be shown in that it can degrade persistent organic compounds,i.e., those which do not naturally decompose within a period of 1, 2, 3,4, 5, or 6 days or 1, 2, 3, 4, 5, or 6 weeks (or more) under normalambient

Aspects of the invention provide methods for treating water, which maycomprise: irradiating a mixture comprising an aqueous fluid comprising afirst amount of bacteria with any permutation of the inventive compositematerial(s) as described herein, with ultraviolet and/or visible lightto obtain a treated aqueous fluid comprising a second amount ofbacteria, wherein the first amount is greater than the second amount ofbacteria. The bacterium may be Gram-positive, Gram-negative, multi-drugresistant or otherwise. Such bacteria may include bacillus, pseudomonas,staphylococcus, and/or micrococcus, such as Virgibacillus, Lactobacillusreuteri, Lactobacillus acidophilus, E. coli, Bacillus anthracis,Bifidohacterium animalis, Bacillus subtilis, etc.) (Helicobacter pylori,enteritis salmonella, Streptococcus thermophilus, Streptococcuspyogenes, Salmonella typhi, mycobacteria, Clostridium tetani, Yersiniapestis, M. luteus, M. roseus, and/or M. varians, e.g., acinetobacterspp., alcaligenes spp., bacillus spp., bordetella spp., campylobacterspp., citrobacter spp., clostridium spp., corynebacterium spp.,escherichia spp., enterobacter spp., enterococcus spp., flavobacteriumspp., klebsiella spp., legionella spp, listeria spp., micrococcus spp.,mycobacterium spp., nocardia spp., proteus spp., providencia spp.,pseudomonas spp., salmonella spp., serratia spp., shigella spp.,staphylococcus spp., streptococcus spp., streptomyces spp.,thermomonospora spp., yersinia spp., etc. Other relevant bacteriumclasses may include acidobacteria, actinobacteria, aquificae,armatimonadetes, bacteroidetes, caldiserica, chlamydiae, chlorobi,chloroflexi, chrysiogenetes, coprothermobacterota, cyanobacteria,deferribacteres, deinococcus-thermus, dictyoglomi, elusimicrobia,fibrobacteres, firmicutes, fusobacteria, gemmatimonadetes,lentisphaerae, nitrospirae, planctomycetes, proteobacteria,spirochaetes, synergistetes, tenericutes, thermodesulfobacteria,thermotogae, and/or verrucomicrobia.

Inventive materials need not include any terminal dicarboxylic acid,particularly terminal dicarboxylic acid, such as citrate, tartrate, anamino acid (e.g., serine, cysteine, aspartate, glutamate, tyrosine,etc.) or enantiomers thereof, or may no more than 5, 4, 3, 2.5, 2, 1,0.5, 0.1, 0.01, 0.001, 0.0001, or 0.00001 wt. %, relative to the totalnanomaterial weight, or total carbonaceous nanomaterial weight, of anyof these, either individually or cumulatively.

Inventive materials need not include any plating such as indium tinoxide, a fluorine-doped tin oxide, and/or quartz glass, or may no morethan 5, 4, 3, 2.5, 2, 1, 0.5, 0.1, 0.01, 0.001, 0.0001, or 0.00001 wt.%, relative to the total nanomaterial weight, of any of these, eitherindividually or cumulatively.

Inventive methods can avoid sol-gel techniques, and may be synthesizedand/or precipitate at pHs of, e.g., 7±0.1, 0.15, 0.2, 0.25, 0.33, 0.4,0.5, 0.6, 0.75, 1, 1.5, 2, or 2.5.

The atomic relationship of Zn to Cu may be in a ratio of, e.g., at least2:1, 1.75:1, 1.65:1, 1:5:1, 1:45:1, 1.4:1, 1.35:1, 1.3:1, 1.25:1, 1.2:1,1.175:1, or 1.15:1 and/or up to 0.75:1, 0.8:1, 0.85:1, 0.9:1, 0.95:1,0.975:1, 1:1, 1.025:1, 1.05:1, 1.075:1, 1.1:1, 1.125:1, 1.15:1, or1.175:1. The CuPc (and/or analog) may be added to the pre-hydrothermalsynthetic solution/mixture in a weight relationship to ZnO of, e.g., atleast 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3,1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, or 1.75 (w/w) % and/or up to20, 17.5, 15, 12.5, 10, 9, 8, 7, 6, 5, 4, 3, 2.5, 2.25, or 2 (w/w) %.The CuPc may be present in the inventive materials, relative to totalmaterial weight, in an amount of, for example, at least 5, 5.5, 6, 6.5,7, 7.5, 7.75, 8, 8.25, 8.5, 8.75, 9, or 9.25 wt. % and/or up to 15, 14,13, 12.5, 12, 11.5, 11.25, 11, 10.75, 10.5, 10.25, 10, 9.75, 9.5, 9.25,9, 8.75, 8.5, 8.25, or 7 wt. %.

Inventive materials may exclude semiconductor materials beyond ZnO (andany inherent properties of CuPc and/or CuPc analogs), for example,indium-tin-oxide, silicon, germanium, tellurium, gallium arsenide,gallium phosphide, gallium arsenide, gallium antimonide, titaniumdioxide (rutile and/or anatase), tin oxide, silicon carbide (3C, 4H,and/or 6H), gray selenium, boron nitride (cubic, hexagonal, and/ornanotube), boron phosphide, boron arsenide, aluminum nitride, aluminumphosphide, aluminum arsenide, aluminum antimonide, indium nitride,indium phosphide, indium arsenide, indium antimonide, cadmium selenide,cadmium sulfide, cadmium telluride, zinc selenide, zinc sulfide, zinctelluride, cuprous chloride, cuprous sulfide, lead selenide, leadsulfide, lead telluride, tin (II) sulfide, tin (IV) sulfide, lead tintelluride, bismuth telluride, barium titanate, strontium titanate,lithium niobate, copper zinc tin sulfide, copper tin sulfide, and/orcopper zinc antimony sulfide, or may comprise no more than 15, 10, 7.5,5, 4, 3, 2.5, 2, 1, 0.5, 0.1, 0.01, 0.001, 0.0001, or 0.00001 wt. %,relative to the total inorganic composite weight, of such materials,either individually or in combination.

Aspects of the invention provide Cu-phthalocyanine (CuPc) used as a ZnOphotosensitizer. Aspects of the invention provide single step synthesesof Cu-phthalocyanine/ZnO hollow nanospheres composite. Aspects of theinvention may influence and/or adjust the size and/or shape of ZnOparticles using Cu-phthalocyanine. Aspects of the invention may enhancethe photocatalytic activity of ZnO nanomaterials by CuPc sensitizationand/or the use of CuPc-sensitized ZnO nanomaterials to decompose one ormore organic pollutants and/or pathogenic bacteria, e.g., under visiblelight irradiation. Moreover, aspects of the invention provide methods ofstabilizing and/or recycling of ZnO as CuPc/ZnO (hollow) nanomaterialsunder solar irradiation.

Aspects of the invention provide a synthesis of Cu-phthalocyanine-ZnOcomposites, which may take the form of nanospheres and/or hollownanospheres. Aspects of the invention may provide one pot and/or singlestep hydrothermal syntheses of such composites.

Aspects of the invention may combine CuPc and ZnO to bring aboutnanostructural modifications to the pure ZnO structure, e.g., as acomposite of preferably hollow shell microspheres having averagediameters of, e.g., at least 1.5, 1.6, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95,2, 2.05, 2.1, 2.15, 2.2, or 2.25 μm and/or up to 2.5, 2.4, 2.3, 2.25,2.2, 2.15, 2.1, 2.05, 2, 1.95, 1.9, 1.85, 1.8, or 1.75 μm, and hollownanospheres of ZnO with average diameters in the range of, e.g., atleast 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, or 225 nm and/orup to 325, 320, 315, 310, 305, 300, 295, 290, 285, 280, or 275 nm, whichcan be distinct from agglomerated ZnO particles formed from pure ZnOsamples in the absence of CuPc. Aspects of the invention may employ CuPcas a templating agent, e.g., for the formation of the hollow nanospheresof ZnO particles. Aspects of the invention include photocatalyticallymineralizing organic pollutants under solar light irradiation withinventive composites. Aspects of the invention provide enhancedphotocatalytic activity by using CuPc/ZnO nanocomposite as compared topure ZnO nanomaterials, evidencing the role of CuPc sensitizing ZnOunder solar light irradiation. Aspects of the invention provideinventive composites as antibacterial agents against bacteria, includingGram-positive and/or Gram-negative bacteria, e.g., E. coli bacteria.

EXAMPLES

Chemicals: 4-nitrophthalonitrile (99.98%), ethanol, diethylene glycol(≥99%), benzene thiol (≥98%, FG), dimethylformamide (DMF) (99.8%), andzinc acetyl acetonate hydrate (99.99%) were purchased fromSigma-Aldrich. 4-Thiophenylphthalonitrile (FIG. 1 , compound 3) wasprepared as described in Molec. Catal. 2017, 433, 68-76, and Photodiag.Photodyn. Ther. 2018, 23, 25-31, each of which is incorporated byreference herein in its in entirety.

Materials Synthesis

Synthesis of tetra(4-thiophenyl)phthalocyaninatocopper(II), (PhS)₄CuPc,(FIG. 1 , compound 4): 4-Thiophenylphthalonitrile (FIG. 1 , compound 3)in a molar amount of 4 of 1 g, 4 mmol and copper (II) chloride (1.22 g,5.5 mmol) were dissolved in 10 mL of dimethylaminoethanol (DMAE). DBU (4mL, 0.04 mmol) was added. The mixture was refluxed, cooled, and thenprecipitated with methanol (25 mL). The solid was filtered off andwashed with water. The crude products purified by column chromatographyto yield (PhS)₄CuPc, (FIG. 1 , compound 4) as a blue solid (8.03 mg,67.8%). ¹H-NMR (DMSO-d6): σ=8.4-8.7 (m, 4H, Pc-H), 8.7-8.9 (m, 8H,Pc-H), 9.2-9.5 (20H, mph) ppm. MS (FD): m/z=1012.75 (M⁺). Elementalanalysis: C₃₆H₃₆N₈S₄Cu, Found C, 65.78, H, 3.61, N, 10.88. Anal. Calcd.C, 66.52, H, 3.67, N, 11.03.

Synthesis of tetra(4-thiophenyl)sulphonated phthalocyaninatocopper(II),(PhS.SO₃Na)₄ CuPc, (FIG. 1 , compound 5):Tetra(4-thiophenyl)phthalocyaninatocopper (II), (PhS)₄CuPc, (FIG. 1 ,compound 4, 1.2 g, 1.2 mmol) was dissolved in 10 mL of fuming sulfuricacid (30% SO₃), added into a quartz tube, then transferred into amicrowave reactor. The reaction temperature was first raised to 80° C.within 5 minutes and maintained for 15 minutes, then raised to 115° C.for 10 minutes, followed by 130° C., maintained for 30 minutes. Themixture was then cooled to room temperature. The solid formed was washedwith column chromatography. A dark blue solution of (PhS.SO₃Na)₄ CuPc(FIG. 1 , compound 5) was evaporated to blue solid (1.3 g, approx. 58%yield). The product, (PhS.SO₃Na)₄ CuPc, (FIG. 1 , compound 5), issoluble in water, ethanol, diethylene glycol, DMF, and DMSO. Themechanism of the overall synthesis of (PhS.SO₃Na)₄ CuPc (compound 5) isshown in FIG. 1 .

Synthesis of CuPc/ZnO hollow nanosphere composites: A CuPc/ZnOnanocomposite was synthesized hydrothermally, in a method which may beaccomplished in one pot and/or one step. In a typical method, 0.1 g (1.7mmol) of CuPc, (PhS)₄CuPc, or (PhS.SO₃Na)₄CuPc, (i.e, the sulfonatedmaterial) was dissolved in 100 mL of a 1:1 solution ofethanol/diethylene glycol. 5 g of zinc acetylacetonate (20 mmol based onanhydrous Zn(acac)₂) were added to the solution of Cu/PC inethanol/diethylene glycol, and the combined solution was stirred for 30minutes. A suspension resulted, and the suspension was then transferredto 250 mL PFTE-lined autoclave, where it was maintained at 150° C. for18 hours at a working pressure of ≤3 MPa or 30 Bar. The product wasseparated by centrifugation, washed 2 times with ethanol and dried at70° C. for 1 hour. The dried solid nanomaterial was weighed to be 1.1 g,indicating that the percentage of CuPc in the nanocomposite sample isapprox. 9 wt. %. Pure ZnO nanoparticles was synthesized by the samemethod without adding CuPc.

Photocatalytic Activity

The photocatalytic performance of the CuPc/ZnO hollow nanospherecomposites were evaluated for the photocatalytic transformation ofCrystal Violet (CV) and as a model water pollutant. The photocatalyticexperiments were carried out using sunlight simulating lamp (PT2192, 125W, mercury vapor bulb producing UVA, UVB, visible light, and heat). Thephotocatalyst (1 g/L) was dispersed in 100 mL of water, followed by 20ppm of Crystal Violet (CV) dye. The resulting suspension was kept in thedark for 30 minutes under stirring to achieve an equilibrium. After theequilibrium was reached, the suspension was irradiated. Liquid sampleswere taken before and during the irradiation, then filtered to separateoff the solid catalyst. The photocatalytic experiment was performed forpure ZnO and pure Cu-phthalocyanine (CuPc) for comparison. Thephotocatalytic experiments were also studied across a pH range, i.e., pH2.5 to 10. The effect of H₂O₂ was also studied by adding 0.5 mL of 30wt. % H₂O₂ to 100 mL of water containing 0.1 g CuPc/ZnO and 20 ppmCrystal Violet (CV) dye.

The reusability and stability of the photocatalysts was also studied bycarrying out the photocatalytic experiment three times using the samephotocatalyst. After each run the nanocomposite particles were collectedand washed with distilled water several times by centrifugation untilall the Crystal Violet (CV) dye was desorbed from the surface of thecatalyst. The photocatalyst was then dried in air over for 1 h at 70° C.for the use in the next run.

In Vitro Antibacterial Studies

Bacterial strains: The antibacterial activity of pure ZnO, pure CuPc,and exemplary CuPc-ZnO composites was evaluated using as test organismsa Gram negative bacterium, Pseudomonas aeruginosa (ATCC 27853), and aGram positive bacterium, Bacillus cereus (ATCC 14579). For activation,each indicator strain was sub-cultured in nutrient culture brothovernight at 37° C. on a shaker at 200 rpm.

Referring now to the drawings, wherein like reference numerals designateidentical or corresponding parts throughout the several views.

FIG. 1 shows the mechanism of the overall synthesis oftetra(4-thiophenyl)-phthalocyaninatocopper (II), (PhS.SO₃Na)₄ CuPc(compound 5), as well as the starting materialstetra(4-thiophenyl)phthalocyaninatocopper(II), (PhS)₄CuPc (compound 4),4-(phenylthio)phthalonitrile (compound 3), benzenethiol (compound 2),and 4-nitrophthalonitrile (compound 1).

FIG. 2 show the x-ray diffraction (XRD) patterns of pure ZnO and anexemplary CuPc-ZnO composite. Pure ZnO and CuPc-ZnO samples show sharpand intense diffraction peaks at 31.8°, 34.4°, 36.3°, 475, 56.6°, 62.9°,66.6°, 68.1°, and 69.2° indicating the formation of a highly crystallinewurtzite-structure (JPCDS 36-1451) of ZnO. No change in the crystallinestructure of ZnO particles was observed upon sensitization with CuPc.

FIG. 3 shows Raman spectra of pure ZnO and an exemplary CuPc-ZnOcomposite.

The Raman spectrum of ZnO exhibits a main peak at 437 cm⁻¹characteristic of wurtzite hexagonal phase ZnO, an E_(2H)-E_(2L) peak at339 cm⁻¹, a lower E₂ peak at 99 cm⁻¹, and an E_(2L) peak at 588 cm⁻¹.The (middled) Raman spectrum of CuPc shows strong bands at 585, 676,1336, and 1521 cm⁻¹, attributable to A_(1g), a band at 1448 cm⁻¹attributable to B_(1g), a band at 1136 cm⁻¹ attributable to A_(2g) inplane vibration, and a slight band at 747 cm⁻¹ attributable to an E_(g)out-of-plane vibration mode. The Raman spectrum of the exemplaryCuPc-ZnO nanocomposite shows all peaks assigned to CuPc, i.e., theA_(1g), A_(2g), B_(1g), and E_(g) modes, in addition to the ZnO peaks at99 cm⁻¹(E₂), weak peak at 437 cm⁻¹(E_(2H)), and the peak at 588 cm⁻¹(E_(1L)), indicating a successful synthesis of the CuPc-ZnOnanocomposite.

FIG. 4 shows Fourier-transform Infrared (FT-IR) spectra of. The (middle)FT-IR spectrum of CuPc shows a typical broadband stretching locatedbetween 3700 to 3100 cm⁻¹, which may be attributed to the overlappedsignal of O—H stretching vibration of sulfonic acid group, absorptionbands at 1123 to 1287 cm⁻¹ attributable to symmetric and asymmetricstretching vibration of C—O—C, strong signal at 1421 and 1508 cm⁻¹attributable to C═C bond stretching of aromatic groups, a speak at 1580cm⁻¹ may be due to stretching vibration of the aromatic C—N group,signal at 1332 cm⁻¹ attributable to C—O bond stretching of carboxylicacid groups, signal near to 1033 to 1093 cm⁻¹ attributable to thearomatic C—C bending vibrations, a peak at 885 cm⁻¹ attributable to Cu—Nstretching vibrations, and bands at 754, 725,680, 570 cm⁻¹ attributableto C—S bond vibration. The (lower) FT-IR spectrum of ZnO shows a band at440 cm⁻¹, which is attributable to Zn—O stretching vibration. The FTIRspectrum of the CuPc-ZnO nanocomposite shows that the main peaks of CuPcand ZnO remain after the sensitization process, indicating the existenceof CuPc and ZnO in the nanocomposite. Moreover, the intensity of broadband between 3700 and 3100 cm⁻¹ attributable to the O—H stretchingvibration of sulfonic group in CuPc decreases, indicating thechemisorption of sulfonate groups onto ZnO surface.

FIG. 5A shows the UV-vis diffuse reflectance spectra of pure CuPc, pureZnO, and an exemplary CuPc-ZnO nanocomposite. The diffuse reflectancespectrum of ZnO (upper spectrum) shows an absorption shorter than 380nm. The (middle) spectrum of the exemplary CuPc-ZnO nanocomposite showsbroad absorption in the visible wavelength region with the band around350 to 550 nm, a typical absorption for a CuPc dye.

For band gap calculations, the reflectance spectra of all samples wereanalyzed using the Kubelka-Munk relation to convert the reflectance intoa Kubelka-Munk function. The band gab energies of the pure ZnO andCuPc/ZnO have been estimated roughly from the intercept of the tangentsof Kubelka-Munk plots as depicted in FIG. 5B. The band gap energy ofpure ZnO nanoparticles determined, i.e., 3.0 eV, is in good agreementwith the reported values. The band gab energy of the exemplary CuPc-ZnOcomposite was estimated to be 2.8 eV. Such a reduction in band gapenergy, i.e., from 3.0 to 2.8 eV, indicates a successful sensitizationof ZnO nanomaterials by copper phthalocyanine (CuPc).

FIG. 6A to 6C and FIG. 7A to 7F show the morphology and structure ofsynthesized samples investigated by scanning electron microscope (SEM)and transmission electron microscope (TEM). The SEM images of pure ZnOand an exemplary CuPc-ZnO composite are presented in FIGS. 6A and 6B.The SEM image in FIG. 6A of pure ZnO shows agglomerations of ZnOparticles with sphere like structures. The SEM image in FIG. 6B of theCuPc-ZnO composite shows a composite of hollow shell microspheres withaverage diameters around 2 μm, e.g., ±0.05, 0.1, 0.15, 0.2, 0.25, 0.33,0.4, 0.5, 0.67, 0.75, 1, 1.5, or 1.75 μm, and hollow nanospheres ofsmall ZnO nanoparticles having diameters in the range of from 200 to 300nm, e.g., average diameters of at least 150, 160, 170, 175, 180, 185,190, 192.5, 195, 197.5, 200, 202.5, 205, 207.5, 210, 215, 220, 225 or250 nm and/or up to 350, 340, 330, 325, 320, 315, 310, 307.5, 305,302.5, 300, 297.5, 295, 292.5, 290, 285, 280, 275, or 250 nm.

The hollow nanospheres may have one end open, as depicted for a smallnumber of such open-face spheres marked with yellow arrowheads in A. 6B.This observation was confirmed further by TEM examination. The SEMresults reveal that CuPc may function as a templating agent for theformation of the hollow nanospheres of ZnO particles, as indicated fromthe CuPc-ZnO composite samples relative to pure ZnO (lacking CuPc).

FIG. 7A to 7F show the results of TEM analysis of pure ZnO and anexemplary CuPc-ZnO composite, indicating a relatively clear morphologyand structure of pure nanoparticles and nanocomposite, allowing themeasurement of different features of the specimens. FIGS. 7A and 7B showTEM images of pure ZnO particles on 500 nm and 100 nm scale, exhibitingsubstantially spherical shapes with a sort of chain-shapedagglomeration, the average size of ZnO particles was estimated around 40nm. FIG. 7C shows a selected area electron diffraction (SAED) pattern ofthe ZnO synthesized, indicating substantial crystallinity in the ZnOparticles, with several rings in the electron diffraction pattern. Thefirst five rings may be attributable to the (100), (002), (101), (102),and (110) planes of the ZnO.

FIG. 7D to 7F show the TEM of the structure of the CuPc-ZnO composite,wherein several nanospheres can be observed. As seen in FIGS. 7D and 7E,showing TEM images of the CuPc-ZnO composite at 500 nm and 200 nm, theaverage diameter of the spheres of the CuPc-ZnO composite can beestimated to be approximately 300 nm, e.g., f 5, 10, 15, 20, 25, 33, 40,50, 67, or 75 nm. The hollow nature of the spheres is apparent in thatthe spheres exhibit bright cores of approx. 200 nm, e.g., ±5, 10, 15,20, 25, 30, 35, 40, 45, 50, or 55 nm, and dark shells of around 100 nm,e.g., ±2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 32.5, or35 nm. As seen in the high magnification TEM image in FIG. 7F, thehollow spheres appear to comprise nanorods with average lengths of a fewtens of nanometers, e.g., at least 10, 12.5, 15, 17.5, 20, 22.5, 25,27.5, or 30 nm and/or up to 100, 90, 80, 75, 70, 65, 60, 55, or 50 nm,and an average thickness of approx. 10 nm, e.g., f 0.05, 0.1, 0.15, 0.2,0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.67, 0.75, 1, 1.25, 1.5, 1.75, 2,2.25, 2.5, 3, 3.5, 4, or 5 nm.

FIG. 8 shows the thermal Gravimetric analysis (TGA) plots of thesynthesized samples. The (upper) TGA plot of pure ZnO, as an inorganicmaterial comprising little pyrolyzable matter, shows no notable weightloss until 1000° C., whereas CuPc is unstable at temperatures aboveapprox. 490° C. The residual mass after heat treatment of CuPc-ZnO aboveapprox. 490° C. may be attributed to the ZnO and CuO because theresidual mass after heat treatment of CuPc-ZnO at above approx. 490° C.may be attributed to the ZnO and CuO. According to the TGA plots, theweight loss of about 8.7% is estimated for the CuPc-ZnO sample,indicating the percentage of loaded CuPc on ZnO nanoparticles. Thisvalue is found to be in agreement of the experimental value.

Photocatalytic Activity

FIG. 9A to 9D show experimental results relevant to the photocatalyticperformance of the synthesized nanomaterials for the oxidation ofCrystal Violet (CV) dye under visible light irradiation. The exemplaryCuPc-ZnO nanocomposite exhibits superior photocatalytic activitycompared to pure ZnO. FIG. 9A shows the UV-vis absorption spectralchange of Crystal Violet (CV) dye in the presence of the exemplaryCuPc-ZnO composite over time, i.e., from 0 to 30 minutes.

FIG. 9B shows the efficiency of Crystal Violet (CV) degradation underdifferent conditions. The Crystal Violet (CV) dye alone exhibits veryslow degradation under visible light, while a faster degradation ratewas observed when ZnO is used as a catalyst. In the presence ofCuPc/ZnO, more efficient degradation has been achieved, resulting in thedegradation of about 82 mol. % of Crystal Violet (CV) dye in only 40minutes, while 100 mol. % of Crystal Violet (CV) dye has been degradedusing CuPc/ZnO composite in the presence of H₂O₂. This enhancement inthe photocatalytic (degradation) activity can be attributed to thesynergism between CuPc and ZnO. 100 mol. % degradation efficiency ofBromophenol blue dye under visible light irradiation has been reportedusing a Ni-phthalocyanine-TiO₂ photocatalyst compared to 32 mol. % usingonly pure TiO₂, in Molec. Catal. 2017, 433, 68-76. Upon visible lightirradiation metallophthalocyanine dyes, e.g., NiPc, CuPc, etc.,generally absorb the visible light forming the excited dye molecules,which may then inject the electrons into the metal oxide, e.g., TiO₂,ZnO, etc., producing active oxygen radical species.

FIG. 9C shows the results of photocatalytic degradation experiments ofCrystal Violet (CV) under various pH values, i.e., 2.5 to 10. As can beseen in FIG. 9C, the best degradation result was obtained near thenatural pH, i.e., pH 5. The photocatalytic degradation was observed toincrease near the zero point of charge of ZnO nanoparticles.

FIG. 9D shows recyclability measurements of the ZnO and the exemplaryCuPc-ZnO nanocomposite systems for the photocatalytic degradation ofCrystal Violet (CV). As seen in FIG. 9D, the photocatalytic activitydecreased 82.4% over three runs with ZnO and 96.34% over three runs withthe exemplary CuPc-ZnO composite, and the decrease was 96.4% forCuPc-ZnO—H₂O₂ (which is not shown). That is, only slight change in thephotocatalytic activity was been observed for the CuPc-ZnO systems after3 runs. This slight decrease in the photocatalytic activity may be dueto slight dissolution of the ZnO nanoparticles or to the desorption ofCuPc molecules from ZnO surface. The results indicate a high stabilityof the synthesized composite nanomaterials.

FIGS. 10A and 10B show UV-vis absorption spectra (FIG. 10A) of anaqueous solution of 2,4-dichlorophenoxyacetic acid (2,4-D) during solarlight irradiation in the presence of CuPc-ZnO—H₂O₂ at pH 5, alongsideplots (FIG. 10B) of the photocatalytic degradation efficiency of2,4-dichlorophenoxyacetic acid (2,4-D) on the basis of concentrationversus initial concentration, C/C₀, as well as total organic contentversus initial total organic content, TOC/TOC₀, with irradiation time atpH 5 in the presence of CuPc-ZnO—H₂O₂.

Evaluation of Antibacterial Activity

The inhibitory activity of the CuPc-ZnO composite materials was assessedagainst multi-drug-resistant (MDR) E. coli by agar well diffusion. Thepresence of a clear zone indicated that the bacteria did not developresistance toward any of the tested chemical compounds. The maximuminhibitory zone was obtained with an exemplary CuPc-ZnO composite,followed by CuPc, and then pure ZnO. These results indicate that alltested materials are active against MDR E. coli.

CU-Phthalocyanine Sensitized Photocatalytic Mechanism

The photocatalytic oxidation of pollutants using copper-phthalocyaninesensitized metal oxide photocatalysts, such organic pollutants includingCrystal Violet (CV) and 2,4-dichlorophenoxyacetic acid (2,4-D) as wellas bacterial damage under solar light irradiation using a CuPc-ZnOcomposite may proceed as proposed in FIG. 12 and Equations 1 to 7.

CuPc+hν(Vis)→CuPc*+(e ⁻)  Eq. 1

CuPc*(e ⁻)+ZnO→.CuPc⁺ZnO(e ⁻)  Eq. 2

ZnO+hν(UV)→ZnO(e ⁻)+ZnO(h ⁺)  Eq. 3

ZnO(e ⁻)+O₂→ZnO+O₂.⁺  Eq. 4

ZnO(h ⁺)+H₂O→.OH  Eq. 5

(O₂.⁻,.OH)+CV→CO₂+H₂O  Eq. 6

(O₂.⁻,.OH)+Bacteria→Damaged Bacteria  Eq. 7

Numerous modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described herein.

1. A photosensitizer composite, comprising:tetra(4-thiophenyl)phthalocyaninatocopper(II); and ZnO particles,wherein the ZnO particles include first spheroid particles and secondspheroid particles, wherein the first spheroid particles have an averagediameter in a range of from 50 to 450 nm and the second spheroidparticles have an average outer diameter in a range of from 0.5 to 5 μm.2-4. (canceled)
 5. The composite of claim 1, wherein the copperphthalocyanine compound is present in an amount of from 2.5 to 15 wt. %,relative to a total material weight.
 6. The composite of claim 1, whichis synthesized hydrothermally.
 7. The composite of claim 1, having amolar ratio of Cu to Zn in a range of from 3:1 to 1:3.
 8. The compositeof claim 1, wherein the first spheroid particles have a sphericity of atleast 0.85, and/or are hollow.
 9. The composite of claim 1, wherein thesecond spheroid particles are hollow spheres having a sphericity of atleast 0.9, and/or hollow hemispheres, which when extrapolated tospheres, have a sphericity of at least 0.9.
 10. The composite of claim1, wherein the second spheroid particles have nanorods, protrudingoutwardly, orthogonally to spherical surfaces, and wherein the nanorodshave an average diameter in a range of from 1 to 250 nm. 11-20.(canceled)